The invention relates to a yarn blow-in valve, in particular for the introduction of textile yarn into yarn guide tubes, such as can be provided for the transfer of yarn from a bobbin creel to a textile machine.
Bobbin creels, which as a rule support a large number of yarn bobbins, are often used for making yarn available to textile machines. A yarn runs from every yarn bobbin to the textile machine which is to be supplied with yarn. Tubes are often used for guiding the yarn, wherein one yarn runs through each tube. Each tube can be several meters long. The yarn is mostly pulled into these tubes by means of compressed air.
For this purpose a yarn blow-in valve is known, for example from U.S. Pat. No. 5,024,393. An air nozzle is arranged opposite the open end of a yarn guide tube, from which compressed air can be expelled, controlled by a valve, which then flushes the yarn into the yarn guide tube. The yarn blow-in valve is located in a compressed air line. The compressed air line, the yarn guide tube and the yarn blow-in valve are mounted outside on a support.
The air nozzle of the yarn blow-in valve is arranged opposite the open end of the yarn guide tube and laterally offset in respect to it in order to permit a lateral guidance of the yarn to the open end of the yarn guide tube. The operation is fixed, for example for right-handed people, because of the asymmetric arrangement.
As a rule, creels for bobbins are assembled at the place of their use from prefabricated elements. The assembly and equipping of the creels with all required elements, such as yarn blow-in valves, for example, should be accomplished in a simple, assembly-friendly manner. Moreover, this should result in a structure which is as accessible as possible. Furthermore, it is necessary to take into consideration that creels are subject to contamination because of the deposition of fluff, the same as almost all devices in textile mills. It is also necessary to counteract this.
One object of the invention is to provide a yarn blow-in valve which is simple to mount.
This and other objects are attained in accordance with one aspect of the invention directed to a yarn blow-in valve constructed in at least two pieces and divided into a base body and a connecting piece. These can be connected with each other by means of a coupling device. In this divided construction, the connecting piece is preferably associated with a compressed air line, and the base body is preferably associated with a yarn guide tube. In this way the connecting piece can first be separately mounted in the compressed air line before it is coupled with the base body, which was also separately mounted. This makes assembly simpler. Moreover, the twopiece embodiment permits the placement of the compressed air line, together with connecting elements, in the interior of hollow profiled sections, for example, or also in profiled sections which are open on one side, such as U-shaped profiled sections or the like which, for example, are used as support elements for the creel or are provided thereon. In this way the compressed air line can be placed so that it is not visible. By means of this the total construction becomes smoother, and fewer hard-to-access surfaces or surface areas result, on which deposits of flux can collect.
The coupling device provides a connection of an air delivery conduit, which is provided with the connecting piece, with an air conduit formed in the base body, and in addition provides the mechanical connection between the connecting piece and the base body. While the connecting piece is used for a connection with the compressed air line which, for example, consists of hoses, an air valve, which leads to a blow nozzle, is provided on the base body. The two parts of the yarn blow-in valve, i.e. the base body and the connecting piece, are arranged on both sides of a wall of the support element. In this case, one member of a coupling projects through an opening in the wall. Essentially there is no necessity for accuracy and precision in connection with the latter, or freedom from burrs, rigidity, etc. More or less play can easily be allowed here without adversely affecting the function. The coupling members, which are preferably complementary, are sealed against each other in a fluid-tight manner, regardless of the size or precision of the opening.
It is considered to be particularly useful to embody the coupling members in such a way that the coupling can be released. A releasable coupling can be constituted, for example, by a snap connection with one or several locking tongues, which are a part of the coupling members. These can secure the base body onto the connecting piece or the connecting piece onto the base body. The coupling device can simultaneously be used for fixing the yarn blow-in valve in place on the support, for example if the support is clamped between the connecting piece and the base body. Alternatively, it is possible to provide additional fastening means on the base body and/or the connecting piece. The fastening means can be screws, locking pins, snap-in tongues, or the like.
In an advantageous embodiment, the coupling members can be rotated in respect to each other, at least over a limited rotation range. Essentially, the axis of rotation is oriented transversely to the passage and parallel with the air delivery conduit. Because of this it is possible to pass hoses for delivering compressed air around the yarn guide tubelets. Moreover, the compressed air hoses, which are designed somewhat longer than required in most cases, can be guided in a meandering fashion in the conduit. Because of the rotatability of the connecting piece it is possible to match it to the course of the hose.
Preferably, the connecting piece has a passage from which the air delivery conduit branches off. The passage is preferably provided with two connections which permit the placement of several connecting pieces, one behind the other in a compressed air line. The connections can be simple hose connectors on which an air hose is pushed.
The valve means arranged in the base body is preferably a ball valve with a ball made of plastic, for example neoprene. It is separated from the actuating element, i.e. not connected with it. The actuating element only has a tappet which, when the element is actuated, pushes the ball off its valve seat. Because of this, lateral play of the actuating element is of no importance for the seal of the valve in the closed state. In the non-actuated state there is a defined distance between the actuating element and the valve closing member. The valve will not yet open with a lateral force acting on the control knob, or with only a very slight actuation of the control knob.
The actuating element can be sealed by gap seals. This can be achieved, for example, by means of a rib-like projection on the control knob, which engages corresponding recesses of the base body. It is therefore made possible that no air escapes when the control knob is actuated by the operator. The control knob, which is pushed, preferably has an edge, which engages a groove of the housing. A gap seal is formed in this way which prevents compressed air from flowing out in the direction of the operator side.
Moreover, simple disassembly, for example for cleaning, is possible by the separation of the actuating element and the valve closing member. The actuating element (control knob) can be designed in such a way that it snaps into the base body, wherein a fastening element, for example a snap-in tongue, is accessible from the outside, so that the control knob can be released from the base body.
The blower nozzle is preferably designed as a relatively long conduit of equal circumferential shape in order to allow the exit of a laminar air jet. The latter is very well bundled and in that way makes satisfactory yarn introduction possible, even into long yarn guide tubes.
A holder for a catch nozzle and a connection for the yarn guide tube are preferably provided on the base body. This holder can be a spring clamp, for example, which is embodied as one piece with the base body, which for example is made of plastic. The spring clamp prescribes an orientation for the catch nozzle and the yarn guide tube, which preferably coincides with the direction of the blower nozzle. In a preferred embodiment, this direction extends at an acute angle in respect to the base surface of the base body. Because of this, the yarn guide tube extends obliquely away from the base body into the profiled support element. It is thus made possible to place the yarn guide tubes inside the profiled support section. The result is a particularly smooth and simple construction, particularly if the yarn guide tubes, as well as the compressed air lines, are arranged on the profiled support section.